I'm new this forum. I've been reading through a lot of the post here and this is great stuff.

I used to have a silver and black TI-99/4A back in the '80s when I was going to college. I had a PEB with 32K card, an RS232 card, a P-code card and the disk controller card with 1 SSSD drive and DSDD (used n DSSD mode), a speech synth and bunch of software and cartridges. Over the year I got rid of all of the hardware and software (kicking myself now!).

So recently I picked up a 99/4A, a PEB with a SSSD drive, RS232 card, a speech synth and 32k side car. I also picked up XB, E/A (complete kit) and a Mini Memory (no cassette, so no Line-by-Line assembler). The console work great! The speech synth works, the PEB works and 32k side car works. However, I'm having an issue with getting the 32k side car and PEB working together. Individually they are working just fine but when I attach both of them to the console at the same time, the console looks up. No spash screen so no way to get to BASIC or XB.

When I power on the PEB, the interface card lights up, then when I power on the memory, the interface light on the PEB goes off. When I power up the console, the interface and RS232 card both light up in the PEB and the console is locked.

The speech synth works when plugged into the memory side card and the with the memory powered on.

What could be the issue with the console, memory side card and PEB not working together? Any ideas on how I could further trouble shoot this issue?

You might want to try cleaning the contacts on the right side of the side car memory expansion.
If nothing's been connected there for some time or maybe never (my best guess), those contacts might be pretty well oxidized.
You can use a pencil eraser for this if you can get it in there, or a second best option would be a q-tip with some
alcohol on it.

I don't think you can run the 32K side-card and PEB together. At least not when you have a 32K memory card in the PEB.
Even if they would be able to run them together, you'd have overlapping RAM areas so no benefit at all.

Could also imagine that the TI PHP 2200 Memory Expansion side car does not carry data/address lines to its side connector ?
I'm sure some of the clever hardware guys can give a better explanation

Similar to retroclouds' suggestion, and this may be obvious, but make sure you don't have a 32K card in the PEB already. It seems strange that TI's own expansion box would not work with the PEB, but I have never physically had access to that specific piece of TI gear.

Are you familiar enough with electronics to check the schematics? You could confirm, either way, that the address / data pins leave the memory box and are available to other modules (like the PEB).

Reasonably, the memory expansion must pass through the bus lines. The whole idea with that type of peripherals was that you could stack them together on the side of the computer. Hence the freight train nick name.

Thanks for the suggestions. There is no 32k memory card in the PED. I have also cleaned the contacts on the side car. Where would I locate schematics for the 32k side car? I have also looked at the 32k side car to see if I could locate any cold solder joint, but I haven't seen any yet.

Mainbyte has good resources, not sure if the schematics for the 32K sidecar are there or not. However, it is possible that the sidecars were made to work with other sidecar expansion, and possibly *not* the PEB, since the PEB seemed to come later, around the time of the 99/4A.

That's what I was starting to think also. I found a copy the PHP 2200 manual and it states the a total of 6 devices can be attached with the speech synth 1st and the memory side care 2nd and then the rest. Not sure it the PEB counts as a single device or not. Guess I'll have to search around for a 32k memory card for the PEB.

... However, it is possible that the sidecars were made to work with other sidecar expansion, and possibly *not* the PEB, since the PEB seemed to come later, around the time of the 99/4A.

They all work together in various combinations, as long as you don't duplicate devices.I've had just about every combination connected together over the years. There's noreason this combination shouldn't work, so it's truly a piece of hardware not functioningcorrectly, probably the sidecar 32k.

When I first acquired a PEB it did not have 32K card but I had a 32K sidecar device. I do not recall having any problems. Later I bought a HRD 4000 card that contained a 32K chip so I had to stop using the sidecar device. After I purchased a SAMS memory card I had to move the 32K chip from the HRD card to the SAMS card where it sits today.

Well, cool, I guess that answers that. So the something in the 32K sidecar is probably failing.

So glefebvre, if you have a means and your soldering skills are up to it, you might try reflowing all the solder joints. I have done this twice with old hardware (coin-op game board and some TI gear). One of the boards had every IC in a socket, so I swapped and tested every IC and they were all good. Only after cleaning, reflowing, and cleaning (again) every solder point did the board work. So it was not any component, but rather just age of the board. That is not always the case, but I have seen it happen.

Rosin core, leaded solder. Same stuff they used to make the board. Do not mix leaded and lead-free solder. New commercial electronics are all lead-free now, but this old stuff is all leaded. Leaded is also easier to work with, and for hobbyists it is fine.

Clean the bottom with 99.9% alcohol (no, the store-bought isopropyl is not good enough for circuit board work, it will leave a residue). I get mine from Mouser (http://www.mouser.co...BtMdYUqbk2mqLFq)

Also, get some no-clean liquid flux and use it on every IC that you reflow. You will also need a solder-sucker, and I recommend a temperature controlled grounded iron (i.e. not the Radio Shack special), but it is up to you.

If you want the "quick and dirty" method, then just heat each joint until the solder is molten, then remove the iron. With flux on the joints, this will go very quickly. Be sure to keep your iron tip tinned!

For a better job, heat each joint and use the solder-sucker to remove the bulk of the old solder. Then go back and resolder each joint with new solder. This will take a little more time than just reheating each joint, but it will be a nicer job. Don't over heat your parts, and take your time.

There are a lot of videos on youtube on soldering and such, and spending some time reviewing is always a good idea if you have not done any rework in a while.

Well, it looks like the side car is okay. I got another PEB and everything works with the new PEB. So, I must have an issue with the first PEB that I bought. I'll have to reflow the solder joint on the connecting cable on the first PEB and see if that fixes the issue with one not working with the side car.